The Expression Of Inflammatory Cytokines In Patients With Irritable Bowel Syndrome

Background & Aims:In recent years,many studies reported inflammation and immunodeficiency were found in intestinal mucosa among the patients suffered from irritable bowel syndrome(IBS),and cytokines secretion dysfunction played a part role in abnormal immune response.However,the specific mechanisms for IBS remain not to be defined.To investigate whether infection and inflammation play an important role in the occurrence of IBS,we examined interleukin(IL)-6,IL-13 and IL-18 expression in plasma and rectal mucosa of IBS patients,particularly post-infection IBS patients.Methods:67 patients were recruited randomly from gastroenterology clinics in our hospital.Individuals aged averagely 42.3±10.86 years who satisfied RomeⅢcriteria for the diagnosis of IBS.These patients were divided into two groups such as diarrhea group and constipation group.23 patients in diarrhea group had acute gastroenteritis or dysentery history, and 4 patients do so in constipation group.20 healthy people were studied as control group.IL-6,IL-13 and IL-18 plasma level of all subjects were measured with enzyme-linked immunosorbent assay(ELISA).Rectal and ileocecal mucosa were taken by routine colonoscopy,and IL-6,IL-13 and IL-18 expression in these mucosa were examined with immunohistochemical assay.The statistic analysis was performed by SPSS for Windows 11.0. Means of continuous variances between group comparisons were performed with T-test or ANOVA.Chi-sguare test was used to compare frequencies. Aαlevel less than 0.05 indicated statistical significance. Results:In diarrhea group,pro-inflammatory cytokines IL-6 and IL-18 positive expression frequency in rectal mucosa were 64%and 70% respectively,which were greater than control group significantly (P＜0.05).In constipation group,those positive expression frequencies were 52%and 41%respectively,which were greater than control group too. However,there was no significant difference between constipation group and control(P＞0.05).Anti-inflammatory cytokine IL-13 positive expression frequency in diarrhea and constipation group were higher than that of control group,but there was no significant difference between two groups respectively(P＞0.05).Pro-inflammatory cytokines IL-6 and IL-18 plasma level were 116.29±43.26 pg/ml and 5.62±4.01 pg/ml in diarrhea group respectively,which were higher than control group markedly(P＜0.05).However,there was no significant difference between constipation group and control(P＞0.05).Anti-inflammatory cytokine IL-13 plasma level(50.35±7.69 pg/ml)in the patients of IBS,which was lower than control,differed no significantly(P＞0.05).Pro-inflammatory cytokines IL-6 and IL-18 plasma level(117.26±45.06 pg/ml & 5.43±4.28 pg/ml)and mucosal positive expression frequencies(60.86%& 56.25%) in post-infection patients were higher than that of no-infection patients respectively,but there were no significant difference between two groups (P＞0.05).IL-6 and IL-18 plasma level and mucosal positive expression frequencies in post-infection patients were greater than control group significantly(P＜0.05).In post-infection patients and no-infection patients anti-inflammatory cytokine IL-13 plasma level(49.63±7.75 pg/ml & 50.61±7.66 pg/ml)and mucosal positive expression frequencies (47.82%&48.14%)were lower than control respectively,however,there were no significant difference between two groups(P＞0.05).Conclusions:①Pro-infLammatory cytokines plasma level and mucosal expression increased in IBS patients,particularly in diarrhea IBS patients,However,anti-inflammatory cytokine level had no significant change.Those changes hinted there was a disbalance of Pro-inflammatory cytokines and anti-inflammatory cytokine not only in the plasma level but also in themucosal expression of patients with IBS.It is possible that the expression of Pro-inflammatory cytokines in plasma is a clinical test faxility,and this will provide new auxiliary diagnosis measure and theory bases for the diagnosis of IBS.②Pro-inflammatory cytokines plasma level and mucosal expression in post-infection irritable bowel syndrome patients were greater than that of no-infection irritable bowel syndrome patients.It suggested that inflammation induced by infection may take part in pathogenesis of IBS and effect the balance of cytokines.